RU2760034C1 - Electric fan for the climate system of a vehicle - Google Patents

Abstract

FIELD: electrical engineering.

SUBSTANCE: invention relates to electrical equipment, in particular, to an electric fan with a brushless direct current engine, intended for the climate system of a vehicle, e.g., a car. The electric fan comprises an impeller coupled with a brushless direct current electric engine including a stator assembly and a rotor assembly coupled with the drive shaft. The rotor assembly is equipped with a movable housing with a magnet installed inside. The stator assembly is equipped with a housing with a magnetic circuit located in the inner space of the housing of the rotor assembly, installed on the outer surface. The housing of the stator assembly is made of plastic and has an axial hole with a drive shaft installed inside through rolling bearings, rigidly coupled with the housing of the rotor assembly and the impeller. Each of said rolling bearings is pressed by an outer ring into the housing of the stator assembly and by an inner ring onto the drive shaft. The housing of the rotor assembly is made of plastic. The magnet is annular and is embedded into the body of the housing of the rotor assembly, wherein said magnet is an embedded part in the process of manufacture of said housing by injection moulding.

EFFECT: increase in the operational reliability of the electric fan, expressed in the reduction in the level of noise and vibrations.

7 cl, 7 dwg

Description

Technology area

The invention relates to electrical equipment, in particular to an electric fan with a brushless DC motor, designed for the climate system of a vehicle, such as a car.

Prior art

In the prior art, brushless DC motors are known comprising a stator assembly and a movable rotor assembly mounted on a drive shaft. In the housing of the rotor assembly, a plurality of magnetic tiles are installed, located along the circumference on the inner surface of the specified housing. The stator unit contains a housing with a magnetic circuit installed on the outer surface and placed inside the movable rotor unit. Brushless motors can be used in the design of an electric fan for the vehicle's climate system.

The prior art knows the design of a brushless motor (see CN 212086045 U, IPC H02K 29/00, H02K 5/16, H02K 1/27, publ. 04.12.2020), in which the stator assembly housing is made of plastic or plastic alloys and contains an axial hole, in which the axle is installed, is fixedly fixed in the housing of the rotor assembly. The axial bore of the stator unit housing is lubricated to reduce friction between the axle and said housing as the rotor unit rotates. To prevent the specified grease from leaking into the housing of the rotor unit, an annular seal is installed in the annular groove of the housing of the stator unit, adjacent to the housing of the rotor unit. The disadvantages of this design can be attributed to its insufficient reliability during long-term operation, since the friction of the axle with the housing of the rotor unit and the specified O-ring will lead to wear of these parts and, as a result, there will be increased noise and vibration, and failure.

A design of a brushless motor with a stator unit and an external rotor unit is known from the prior art (see DE 102006059135 A1, publ. 2008.06.26, IPC H02K1 / 27, H02K 15/02). The magnets of the rotor assembly are fixed with a gap relative to each other on the outer metal yoke and are filled with plastic for their fixation, thus forming the body of the rotor assembly, consisting of the outer metal yoke and plastic sections of the housing, in particular, the bottom and top sections. The stator assembly is provided with a magnetic circuit located on the outer surface of the stator assembly housing. Through the axial bore of the stator unit housing, a drive shaft runs, mounted on two bearings, one of which is pressed into the said housing, and the second bearing is pressed into the axial bore of the magnetic circuit. In this case, a cylindrical spring is supported on the outer ring of the second bearing to pre-tension the second bearing.

The known engine can perform its function in an electric fan of a vehicle's air conditioning system. However, the many parts of the motor and the increased precision of the rotor assembly with bearing pretension complicate the manufacture and assembly of the motor. In addition, the presence of a spring supported on a bearing can cause noise during long-term operation at low temperatures, since the sliding fit of the bearing on the outer ring when grease thickens in the bearing and heat shrinkage can lead to unauthorized rotation of the spring relative to the outer ring of the bearing, which reduces reliability of the design.

From the prior art, the design of a brushless motor with a stator unit and an external rotor unit is known, adopted as the closest analogue (see DE 102009023080 A1, publ. 2010.12.02., IPC H02K 1/18, H02K 5/16). The stator unit contains a housing with a flange made in the form of a single piece by injection molding from plastic. The magnetic circuit of the stator assembly is fixedly mounted on the outer surface of the said housing, while their fixedness is ensured by ribs protruding on the housing and located in the recesses of the magnetic circuit. The rotor unit contains a housing, on the inner surface of which a magnet is fixed, covering the stator magnetic circuit from the outer side. The motor drive shaft is installed through two bearings in the axial bore of the stator housing and is fixedly connected through the hub to the rotor unit by one of its end sections, while these bearings are preloaded with one or more springs.

The known engine can perform its function in an electric fan of a vehicle's air conditioning system. However, it has a relatively complex structure, requiring precision manufacturing of the stator to ensure reliable connection of the magnetic circuit with the housing. In addition, due to the presence of separate spring compensators that provide bearing preload and compensate for thermal expansion, the design assumes a sliding fit of at least one of the bearing rings, which, during long-term operation, can cause vibration and noise, leading to a decrease in the reliability of the design.

Disclosure of invention

The technical result consists in increasing the operational reliability of the electric fan, expressed in reducing noise and vibrations.

To achieve the technical result, the electric fan comprises an impeller associated with a brushless DC electric motor, which includes a stator assembly and a rotor assembly associated with a drive shaft; the rotor assembly is provided with a movable housing with a magnet installed inside; the stator unit is equipped with a housing with a magnetic circuit mounted on the outer surface located in the inner space of the housing of the rotor unit, while the said housing of the stator unit is made of plastic and has an axial bore with a drive shaft installed inside through rolling bearings, fixedly connected to the housing of the rotor unit and the impeller, moreover, each of said rolling bearings is pressed with an outer ring into the stator unit housing, and with the inner ring onto the drive shaft, according to the invention, the rotor unit housing is made of plastic, and the magnet has an annular shape and is embedded in the body of the rotor unit housing, while said magnet is a mortgage part in the process of manufacturing the specified body by injection molding.

The housing of the stator unit contains a flange made of plastic and constituting a single whole with the said housing.

The drive shaft can be made of plastic and be integral with the housing of the rotor unit, while the specified drive shaft has an axial hole in which elements are installed that expand the specified drive shaft in the seating zones of the inner rings of the rolling bearings.

The rotor assembly housing can be part of the impeller and be integral with it.

The plastic can be polycarbonate, or glass-reinforced polyamide, or talc-reinforced polyamide, or composite materials.

The rotor assembly magnet can be made from a compressed mixture of magnetic powder and plastic.

The magnetic circuit of the stator assembly can be made of a mixture of iron powder and plastic compressed under pressure.

The set of features of the claimed invention is in a causal relationship with the achieved technical result and is presented in the claims.

The essence of the technical solution is illustrated by the figures.

FIG. 1 schematically shows an electric fan for the vehicle climate system, general view.

FIG. 2 shows the explosive diagram of FIG. 1.

FIG. 3 - schematically shows an electric fan, section along the drive shaft.

FIG. 4 - shows an explosion diagram of the stator assembly.

FIG. 5 - shows the stator, view from the side of the flange.

FIG. 6 is a schematic representation of a rotor assembly with an impeller.

FIG. 7 schematically shows a rotor assembly forming a single whole with the impeller, a section along the drive shaft.

The above figures show:

1 - impeller;

2 - rotor unit;

3 - stator unit;

4 - drive shaft;

4a - peripheral portion of the drive shaft 4;

5 - body of the rotor unit 2;

5a - the outer surface of the housing 5;

6 - magnet;

6a - the inner surface of the magnet 6;

6b - the outer surface of the magnet 6;

7 - magnetic core of the stator unit 3;

8 - housing of the stator unit;

8a - the outer surface of the housing 8;

9 - wires;

10 - flange;

11 - mounting holes;

12 - mounting holes;

13 - electronic board;

14 - axial hole of the housing 8;

15 - bearing;

16 - bearing;

17 - axial hole of the drive shaft 4;

18 - element;

19 - element;

20 - protective case;

21 - fasteners;

22 - hole.

It should be understood that those skilled in the art will be able to suggest other embodiments of the invention and that some of its details may be varied in various other aspects without departing from the spirit and scope of the present invention. Accordingly, the figures and detailed description of an electric fan for a vehicle climate system are illustrative and not restrictive.

The electric fan contains an impeller 1 associated with a brushless DC electric motor (hereinafter referred to as the motor), including the rotor assembly 2 and the stator assembly 3, connected to the drive shaft 4 (hereinafter referred to as the shaft) (see Figs. 1 - 3).

The rotor unit 2 is equipped with a movable body 5 with a magnet 6 installed inside, made of an annular shape and multi-pole. The specified body 5 has a bowl-like shape with an internal space N.

The body 5 of the rotor unit 2 is made of plastic, while the magnet 6 is embedded in the body of the said body 5 in such a way that the inner surface 6a of the magnet 6 is free and faces towards the magnetic core 7 installed in the inner space N of the body 5 with insulated windings of wires 9 of the stator unit 3, and the outer surface 6b of the magnet 6 is filled with said plastic. Thus, the outer surface 5a of the housing 5 of the rotor unit 2 is made of the aforementioned plastic and does not contain the outer metal yoke used in the construction of the engine described in DE 102006059135 A1.

The housing 5 of the rotor unit 2 is made of plastic having high elastic and strength characteristics, and having a low tolerance for shrinkage during injection molding.

For the manufacture of magnet 6, you can use a magnetoplast, which is a mixture of magnetic powder and plastic compressed under high pressure, which has a high manufacturing accuracy and does not require further mechanical processing.

Since the specified magnet 6 has an annular shape, then its magnetic field is directed to the center of the specified ring and closed on its outer surface. The properties of the magnet 6 described above make it possible to use it as an embedded part in the process of manufacturing the housing 5 of the rotor unit 2 by injection molding. The specified magnet 6 is pre-magnetized and then filled with plastic on an injection molding machine, which ensures a reliable one-piece connection of the magnet 6 with the case 5 and excludes the additional operation of their assembly.

The stator unit 3 contains a housing 8, on the outer surface 8a of which a magnetic circuit 7 with insulated windings of wires 9 is stationary.

The housing 8 of the stator assembly 3 contains a flange 10 with mounting holes 11, 12 for the corresponding fastening of the electronic board 13 of the motor control and the output of the wires 9 of the magnetic circuit 7 (see Fig. 4, 5). The housing 8 with the flange 10 of the stator unit 3 are made of plastic, while the specified flange 10 is with the specified housing 8 a single whole, that is, a single piece.

The housing 8 of the stator unit 3 has an axial bore 14, in which a shaft 4 is installed through rolling bearings 15, 16, and is fixedly connected to the housing 5 of the rotor unit 2 and the impeller 1. Each of these rolling bearings 15, 16 is installed in the axial bore 14, while It is pressed with its outer ring into the housing 8 of the stator unit 3, and with its inner ring onto the shaft 4. One of the free peripheral sections 4a of the drive shaft 4 is fixedly mounted in the axial holes of the housing 5 of the rotor unit 2 and the impeller 1.

Ball bearings can be used as rolling bearings 15, 16.

The housing 8 with the flange 10 of the stator unit 3 are made of plastic, which has high elastic and strength characteristics, and has a low shrinkage tolerance during injection molding, for example, on an injection molding machine.

It is preferable that the housing 5 of the rotor unit 2 and the housing 8 with the flange 10 of the stator unit 3 are made of the same material, i.e. of one type of plastic, which eliminates the difference in linear thermal expansion and does not require additional compensation springs, which can cause noise.

The ductility and elasticity of the housing 8 of the stator assembly 3 allow to ensure optimal interference fits at the junctions of the said housing 8 with the rolling bearings 15, 16 inside the axial bore 14 and the magnetic circuit 7 on the outer surface 8a, and also prevents the occurrence of unacceptable axial forces on the rolling bearings 15 , 16 during thermal expansion, when temperature differences occur during the operation of the electric fan, which makes it possible to exclude from the design additional elastic compensators that protect the rolling bearings 15, 16 from premature wear, seizure and / or destruction.

It should be noted that pressing one of the rolling bearings, in particular the rolling bearing 15, into the axial hole 14 of the housing 8 in the zone W of the location of the magnetic circuit 7, expands the specified housing 8 in the specified zone W, thereby reliably fixing the specified magnetic circuit 7 on the outer surface 8a of the housing 8. This design provides a reliable fixed connection of the outer ring of the rolling bearing 15 and the magnetic circuit 7 with the housing 8 of the stator assembly 3.

The aforementioned magnetic circuit 7 is made of iron, which is a mixture of iron powder and plastic compressed under high pressure. The specified ferroplast has a functional similarity with a set of insulated charge plates to exclude parasitic Foucault currents in an alternating magnetic field and to close the magnetic fluxes when the engine is running. The use of ferroplast makes it possible to manufacture the stator casing 8 3 from plastic.

The above-described housing 5 of the rotor unit 2 can be part of the impeller 1 and be integral with it. The said housing 5 and the impeller 1 can be made in the form of an integral unit of the same type of plastic by injection molding, while the magnet 6, as described above, is a built-in part and is embedded in the body of the housing 5. This design also makes it possible to reduce noises and vibrations during the operation of the electric fan by reducing the movable joints in the structure (reducing the number of individual engine parts).

In one embodiment, said shaft 4 can be made, for example, of metal as a separate piece.

In another embodiment, the shaft 4 is made of plastic and forms a single whole with the housing 5 of the rotor unit 2, i.e., an integral unit, while the magnet 6, as described above, is embedded in the body of the housing 5 of the rotor unit 2 (see figure 6). Advantageously, the housing 5 and the shaft 4 are made of the same type of plastic by means of injection molding, with the magnet 6 being the embedded part.

In another embodiment, the shaft 4 is made of plastic and forms a single whole with the housing 5 of the rotor 2 and the impeller 1, i.e., an integral unit, while the magnet 6, as described above, is embedded in the body of the housing 5 of the rotor 2 ( see figure 7). Advantageously, the impeller 1, the housing 5 and the shaft 4 are made of the same type of plastic by injection molding, whereby the magnet 6 is an embedded part.

The above-described embodiments of the rotor unit 2, impeller 1 and shaft 4 greatly simplify the manufacture and assembly of the rotor unit 2 and, accordingly, the electric fan, lead to a decrease in noise and vibration, since the number of parts mated during the assembly process is minimized, axial forces on the bearings are practically excluded in them. rolling 15, 16, arising from temperature differences, which generally increases the operational reliability of the electric fan.

Shaft 4, made of plastic, has an axial bore 17, in which elements 18 and 19 are installed, expanding from the outside the specified shaft 4 in the respective landing zones of the rolling bearings 15 and 16. In a specific example of execution, the specified elements 18, 19 are used screws screwed into the axial hole 17 from the opposite end sides of the shaft 4. During the installation of the elements 18, 19 into the axial hole 17, the shaft 4 expands in the inner rings of the rolling bearings 15, 16, which ensures a secure fit on the shaft 4 of the indicated inner rings of the rolling bearings 15, 16 without any additional fasteners.

The operational reliability of the electric fan described above is expressed in the reduction of noise and vibrations due to the implementation of the housing 5 of the rotor unit 2 from plastic with the annular magnet 6 embedded in its body, the tight fit of the rolling bearings 15, 16 along the outer ring into the housing 8 of the stator unit 3, and along the inner ring on the shaft 4, while the function of a flexible compensator to provide preload is performed by the specified elastic plastic housing 8 of the stator assembly 3, and the plastic shaft 4 made of the same material excludes the effect of thermal expansion on the silent operation of the electric fan.

The electronic board 13, mounted on the flange 10 of the housing 8 of the stator assembly 3, is closed from above with a protective housing 20, which prevents solid microparticles and moisture from entering it with the air flow entering the electric fan. The protective case 20 together with the electronic board 13 are attached by means of fasteners 21 to the specified flange 10 through the mounting holes 11. The fasteners 21 can be screws or bolts, or other fastening devices performing a similar function with a similar result. To the electronic board 13 are connected, for example by soldering, the ends of the wires 9 of the insulated windings of the magnetic circuit 7 of the stator assembly 3.

On the outer side of the protective case 20, an opening 22 can be made for fastening to the casing (not shown in the figures) of the electric fan, and openings are provided for leading out the wires of the electric fan.

In the process of operation of the electric fan, the magnetic circuit 7 with insulated windings of wires 9 of the stator assembly 3 is fixedly installed in the inner space N of the housing 5 of the rotor assembly 2, while the specified magnetic circuit 7 surrounds the magnet 6 with a certain working gap. The specified housing 5 with a magnet 6 rotate around the magnetic circuit 7 with insulated windings of wires 9, while the shaft 4 rotates inside the housing 8 of the stator 3. The motor control is regulated through the electronic board 13.

The term "plastic" should be understood as a wide range of materials with high elastic and strength characteristics, low shrinkage tolerance during injection molding. Such materials include, for example, polycarbonate or glass-reinforced polyamide, or talc-reinforced polyamide, or composite materials.

The above described assemblies of the rotor 2 and the stator 3 are characterized by increased reliability, since Rolling bearings are used instead of sleeve bearings, do not contain any sealing parts and compensators for thermal expansion, which, when worn, can cause increased noise, which entails their replacement. In addition, the above-described embodiments of the rotor assembly 2 with the impeller 1 and / or the shaft 4 make it possible to create a compact, quiet, reliable in operation, small-part electric fan, which is easy to maintain during operation.

The above-described electric fan equipped with a brushless DC motor can be used in the climate system of a vehicle such as an automobile.

Claims (7)

1. An electric fan containing an impeller associated with a brushless DC electric motor, including a stator assembly and a rotor assembly associated with a drive shaft; the rotor assembly is provided with a movable housing with a magnet installed inside; the stator unit is equipped with a housing with a magnetic circuit mounted on the outer surface located in the inner space of the housing of the rotor unit, while the said housing of the stator unit is made of plastic and has an axial bore with a drive shaft installed inside through rolling bearings, fixedly connected to the housing of the rotor unit and the impeller, moreover, each of the said rolling bearings is pressed with the outer ring into the housing of the stator unit, and with the inner ring onto the drive shaft, which is different in that the body of the rotor unit is made of plastic, and the magnet has an annular shape and is embedded in the body of the body of the rotor unit, while the specified magnet is an embedded part in the process of manufacturing said body by injection molding. 2. An electric fan according to claim 1, characterized in that the stator assembly housing comprises a flange made of plastic and constituting an integral whole with said housing. 3. The electric fan according to claim 1, characterized in that the drive shaft is made of plastic and is integral with the housing of the rotor assembly, while said drive shaft has an axial hole in which elements are installed that expand the specified drive shaft in the seating zones of the inner rings of the bearings rolling. 4. The electric fan according to claim 1 or 3, characterized in that the housing of the rotor assembly is part of the impeller and is integral with it. 5. An electric fan according to claim 1 or 3, characterized in that the plastic used is polycarbonate, or glass-reinforced polyamide, or talc-reinforced polyamide, or composite materials. 6. The electric fan according to claim 1, characterized in that the magnet of the rotor assembly is made of a mixture of magnetic powder and plastic compressed under pressure. 7. The electric fan according to claim 1, characterized in that the magnetic circuit of the stator assembly is made of a mixture of iron powder and plastic compressed under pressure.

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